Electric lead for vapor electric apparatus.



G. A. KRAUS & R. D. MAILEY.

ELECTRIC LEAD FOR VAPOR ELECTRIC APPARATUS.

APPLIOATION FILED JUNE 30, 1910. A

Patented Aug. 19, 1913.

I I I 0. A. KRAUS & R. D. MAILEY.

ELECTRIC LEAD FOR VAPOR ELECTRIC APPARATUS.

' APPLICATION FILED JUNE 30, 1910. L7Q6l 5,, Patented Aug. 19, 1913.

2 SHEETS-SHEET 2.

. Alva/g7? M%4W di 64.3. $54k V v UNITED STATES PATENT oFFIo CHARLES A. KItAUS, OF NEWTON HIGHLANDS, AND ROY D. MAILEY, OF LYNN MASSACHUSETTS.

ELECTRIC LEAD FOR VAPOR ELECTRIC APPARATUS.

Specification of Letters Patent.

Patented Aug. 19,1913.

Application filed June 30, 1910. Serial No. 569,701.

To all whom it may concern:

Be it known that we, CHARLES A. KnAus and. Bor D. MAnlnY, both citizen of the United States, and residents, respectively, of Newton Highlands and Lynn, in the counties of Middlesex and Essex and State of Massachusetts, have invented new and useful In'iprovements in Electric Leads for Vapor Electric Apparatus, of which the following is a specification. l

Our invention relates to the construction of electrode leads for mercury arc rectifiers or analogous vapor electric apparatus and has for its object particularly to improve the electrical efficiency of mercury cathode leads by providing adequate electro-conductive surfaces in contact with the mercury and also to control the temperature of the cathode by carrying away developed heat through the cathode lead.

In the construction of vapor electric apparatus having a large current capacity difliculty is encountered by reasonof inferior conductivity of the mercury which usually constitutes the cathode of such apparatus, as exemplified by the case of the mercury arc rectifier. Although the body of mercury in the cathode may be of suflicient bulk and extent to operate properly in conjunction with the anodes, the current through the cathode lead is liable to produce excessive temperature by the generation of heat at contact between the mercury and the solid metal of which the lead is composed, and this endangers the efficiency and permanency of the apparatus. Our improvements herein described are addressed to this situation and provide a mercury cathode lead which though of large extent where contact is made with the mercury, is of conveniently small proportions elsewhere which makes formation of the necessary sealing joint practical and easy.

In the drawings hereto annexed which illustrate our invention, Figure 1 shows in vertical section a mercury arc rectifier with a metal container and Fig. 2 is' a horizontal section drawn through the container of Fig. 1 so as to show the cathode foot.

In these drawings A represents the cylindrical, container to which is sealed the cover R. Anodes C and D are suspended upon leads C and D and are suitably connected to operate with the mercury cathode B which is contained in the insulating cup or lining E in the bottom of the container.

sulating material B which descends below the surface of the cathode.

The large extent of the disk shaped foot B furnishes so ample a contact with the mercury of the cathode B that undue local heating due to electrical resistance is in large measure avoided. In many instances the provision of ample electrical contact and theconsequent reduction of heat generated through resistance will suflice to keep the temperature of the cathode within proper limits. If, however, the apparatus is of large current capacity other provisions for controlling the temperature are to be recommended. Thus in the apparatus illustrated in the drawings the stem portion B and foot portion B of the cathode lead are made hollow and an inner tube B is introduced from the top, extending to the lower opening B within the hollow foot. An outlet is provided at B communicating with the interior of the stem portion B. By introducing a cooling fluid through the inner tube B into the hollow foot B and thence through the stem B and out at the aperture B the temperature of the cathode lead and mercury cathode may be effectively controlled and the heat generated by the operation of the apparatus disposed of.

The cathode lead-foot B is substantially of the same extent as the mercury pool which constitutes the cathode proper, B. In all apparatus of this character the current does not enter the cathode surface uniformly, or even constantly atone place, the locus of current entrance, called the cathodespot, wanders over the mercury surface, without apparent rule or regularity. Therefore the heat effects are concentrated first at one place and then at another. Mercury is arelatively poor conductor of heat; iron conducts heat about ten times as readily, copper about fifty times. Moreover, in a mercury cathode the heating initiates at the surface of'the mercury, and is conveyed to the deeper portions of the mercury pool by conduction much more than by convection.

With a cathode lead-foot such as B, composed of iron or steel, the depth of mercury which overlies it can be reduced to a small dimension, and the cooling effect will thus be uniformly felt,- no matter where the cathode spot may wander on the mercury surface. Again, substantially all the mercury which constitutes the cathode pool lies over the upper surface of the lead-fo0t, a circumstance which in conjunction with the cooling effect of the extended lead-foot, enables an apparatus of high capacity to operate vwith a relatively small Weight of mercury.

What we claim and desire to secure by 5 Letters Patent is:

In a vapor electric apparatus a container, a mercury cathode therein and a cathode lead comprising a hollow foot substantially coextensive with the cathode surface.

Signed by us at Boston, Massachusetts, this twenty-second day of June, 1910.

CHARLES A. KRAUS. ROY D. MAILEY.

Witnesses:

CHARLES D. WOODBERRY, JOSEPHINE H. RYAN. 

